This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Gillman, T. Articles by Hallowes, R. C. Search for Related Content PubMed PubMed Citation Articles by Gillman, T. Articles by Hallowes, R. C.

Ultrastructural and Histochemical Observations on a Transplantable Reticuloendothelial Tumor in Rats

Institute of Animal Physiology, Agricultural Research Council, Brabraham, Cambridge, England [T. G.], and Department of Pathology, Imperial Cancer Research Fund, Lincoln's Inn Fields, London, WC2A 3PX, England [R. C. H.]

Tumors induced in inbred Wistar rats by repeated injections of trypan blue occur in the liver and portal lymph nodes and can be transplanted. The ultrastructure and histochemistry of these tumors are described. Ultrastructural studies demonstrated that the cells in both primary and transplanted tumors were pleomorphic mesenchymal cells with numerous cytoplasmic pseudopodial processes and associated with electron-dense, nonperiodic fibrillar material in the intercellular ground substance. The enzymes nonspecific alkaline phosphatase and the specific phosphatases of adenosine mono- and triphosphate were localized round the tumor cells. Cystic spaces were seen in induced primary tumors but not in transplanted tumors or their metastases. The spaces contained histiocytic cells that were rarely associated with fibrillar material or with phosphatase enzymes. These cells were present, however, in the transplantable tumors in which many resembled the tumor cells that were associated with fibrils. Also they resembled morphologically the bi- and multinucleate cells seen in all the tumors. These results would be compatible with the tumor cells being histocytes of endothelial origin.

Received 3/ 3/72. Accepted 7/28/72.